What did your character want to be when they were just a kid. (This can be in and/or out of character.)
IC: Lucy grew up always loving detective shows, and playing cops and robbers with her cousins. Always drawn to the Crime, Mystery, Suspense books. (Particularly Sherlock Holmes, but others...
Actually, the only thing that wasn't stolen at the Louvre's Apollo Gallery is the Regent Diamond, figure no one would take it because something to do with a curse.
I've also found that the two thieves were leaving for Algeria, thanks of a trace of DNA evidence recovered from a helmet and their past in burglary cases according to the police.